/*
 * Created on 14-Jun-2004
 * Created by Paul Gardner
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package com.aelitis.net.upnp.impl.ssdp;

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

import org.gudy.azureus2.core3.util.AEMonitor;
import org.gudy.azureus2.core3.util.AERunnable;
import org.gudy.azureus2.core3.util.Debug;
import org.gudy.azureus2.core3.util.SystemTime;

import com.aelitis.azureus.core.util.NetUtils;
import com.aelitis.net.upnp.UPnPException;
import com.aelitis.net.upnp.UPnPSSDP;
import com.aelitis.net.upnp.UPnPSSDPListener;
import com.aelitis.net.upnp.impl.SSDPIGD;
import com.aelitis.net.upnp.impl.SSDPIGDListener;
import com.aelitis.net.upnp.impl.UPnPImpl;

/**
 * @author parg
 * 
 */

public class SSDPIGDImpl implements SSDPIGD, UPnPSSDPListener {
    private UPnPImpl upnp;
    private SSDPCore ssdp_core;

    private boolean first_result = true;
    private long last_explicit_search = 0;

    private List listeners = new ArrayList();

    protected AEMonitor this_mon = new AEMonitor("SSDP");

    public SSDPIGDImpl(UPnPImpl _upnp, String[] _selected_interfaces)

    throws UPnPException {
        upnp = _upnp;

        ssdp_core = SSDPCore.getSingleton(upnp.getAdapter(), UPnPSSDP.SSDP_GROUP_ADDRESS, UPnPSSDP.SSDP_GROUP_PORT, 0, _selected_interfaces);

        ssdp_core.addListener(this);
    }

    public SSDPCore getSSDP() {
        return (ssdp_core);
    }

    public void start()

    throws UPnPException {
        try {
            upnp.getAdapter().createThread("SSDP:queryLoop", new AERunnable() {
                public void runSupport() {
                    queryLoop();
                }
            });

        } catch (Throwable e) {

            Debug.printStackTrace(e);

            throw (new UPnPException("Failed to initialise SSDP", e));
        }
    }

    public void searchNow() {
        long now = SystemTime.getCurrentTime();

        if (now - last_explicit_search < 10000) {

            return;
        }

        last_explicit_search = now;

        search();
    }

    public void searchNow(String[] STs) {
        ssdp_core.search(STs);
    }

    protected void queryLoop() {
        while (true) {

            try {
                search();

                Thread.sleep(60000);

            } catch (Throwable e) {

                Debug.printStackTrace(e);
            }

        }
    }

    protected void search() {
        ssdp_core.search(new String[] { "upnp:rootdevice" });
    }

    public void receivedResult(NetworkInterface network_interface, InetAddress local_address, InetAddress originator, String usn, URL location,
            String st, String al) {
        try {
            this_mon.enter();

            if (st.equalsIgnoreCase("upnp:rootdevice")) {

                gotRoot(network_interface, local_address, usn, location);
            }
        } finally {

            first_result = false;

            this_mon.exit();
        }
    }

    public void receivedNotify(NetworkInterface network_interface, InetAddress local_address, InetAddress originator, String usn, URL location,
            String nt, String nts) {
        try {
            this_mon.enter();

            if (nt.indexOf("upnp:rootdevice") != -1) {

                if (nts.indexOf("alive") != -1) {

                    // alive can be reported on any interface

                    try {

                        InetAddress dev = InetAddress.getByName(location.getHost());

                        byte[] dev_bytes = dev.getAddress();

                        boolean[] dev_bits = bytesToBits(dev_bytes);

                        // try and work out what bind address this location corresponds to

                        NetworkInterface best_ni = null;
                        InetAddress best_addr = null;

                        int best_prefix = 0;

                        List<NetworkInterface> x = NetUtils.getNetworkInterfaces();

                        for (final NetworkInterface this_ni : x) {

                            Enumeration<InetAddress> ni_addresses = this_ni.getInetAddresses();

                            while (ni_addresses.hasMoreElements()) {

                                InetAddress this_address = ni_addresses.nextElement();

                                byte[] this_bytes = this_address.getAddress();

                                if (dev_bytes.length == this_bytes.length) {

                                    boolean[] this_bits = bytesToBits(this_bytes);

                                    for (int i = 0; i < this_bits.length; i++) {

                                        if (dev_bits[i] != this_bits[i]) {

                                            break;
                                        }

                                        if (i > best_prefix) {

                                            best_prefix = i;

                                            best_ni = this_ni;
                                            best_addr = this_address;
                                        }
                                    }
                                }
                            }
                        }

                        if (best_ni != null) {

                            if (first_result) {

                                upnp.log(location + " -> " + best_ni.getDisplayName() + "/" + best_addr + " (prefix=" + (best_prefix + 1) + ")");
                            }

                            gotRoot(best_ni, best_addr, usn, location);

                        } else {

                            gotAlive(usn, location);
                        }
                    } catch (Throwable e) {

                        gotAlive(usn, location);
                    }
                } else if (nts.indexOf("byebye") != -1) {

                    lostRoot(local_address, usn);
                }
            }
        } finally {

            first_result = false;

            this_mon.exit();
        }
    }

    public String[] receivedSearch(NetworkInterface network_interface, InetAddress local_address, InetAddress originator, String ST) {
        // not interested, loopback or other search

        return (null);
    }

    protected boolean[] bytesToBits(byte[] bytes) {
        boolean[] res = new boolean[bytes.length * 8];

        for (int i = 0; i < bytes.length; i++) {

            byte b = bytes[i];

            for (int j = 0; j < 8; j++) {

                res[i * 8 + j] = (b & (byte) (0x01 << (7 - j))) != 0;
            }
        }

        return (res);
    }

    protected void gotRoot(NetworkInterface network_interface, InetAddress local_address, String usn, URL location) {
        for (int i = 0; i < listeners.size(); i++) {

            try {
                ((SSDPIGDListener) listeners.get(i)).rootDiscovered(network_interface, local_address, usn, location);

            } catch (Throwable e) {

                Debug.printStackTrace(e);
            }
        }
    }

    protected void gotAlive(String usn, URL location) {
        for (int i = 0; i < listeners.size(); i++) {

            try {
                ((SSDPIGDListener) listeners.get(i)).rootAlive(usn, location);

            } catch (Throwable e) {

                Debug.printStackTrace(e);
            }
        }
    }

    protected void lostRoot(InetAddress local_address, String usn) {
        for (int i = 0; i < listeners.size(); i++) {

            try {
                ((SSDPIGDListener) listeners.get(i)).rootLost(local_address, usn);

            } catch (Throwable e) {

                Debug.printStackTrace(e);
            }
        }
    }

    public void interfaceChanged(NetworkInterface network_interface) {
        for (int i = 0; i < listeners.size(); i++) {

            try {
                ((SSDPIGDListener) listeners.get(i)).interfaceChanged(network_interface);

            } catch (Throwable e) {

                Debug.printStackTrace(e);
            }
        }
    }

    public void addListener(SSDPIGDListener l) {
        listeners.add(l);
    }

    public void removeListener(SSDPIGDListener l) {
        listeners.remove(l);
    }
}
